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Android 下载文件及写下SD卡

热度：72   发布时间：2016-05-01 10:59:52.0
Android 下载文件及写入SD卡

Android 下载文件及写入SD卡,实例代码

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Main.xml代码 ?收藏代码
  1. <?xml?version="1.0"?encoding="utf-8"?>??
  2. <LinearLayout?xmlns:android="http://schemas.android.com/apk/res/android"??
  3. ????android:orientation="vertical"??
  4. ????android:layout_width="fill_parent"??
  5. ????android:layout_height="fill_parent"??
  6. ????>??
  7. <Button????
  8. ????android:id="@+id/downloadTxt"??
  9. ????android:layout_width="fill_parent"???
  10. ????android:layout_height="wrap_content"???
  11. ????android:text="下载文本文件"??
  12. ????/>??
  13. ??
  14. <Button????
  15. ????android:id="@+id/downloadMp3"??
  16. ????android:layout_width="fill_parent"???
  17. ????android:layout_height="wrap_content"???
  18. ????android:text="下载MP3文件"??
  19. ????/>??
  20. </LinearLayout>??

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Androidmanifest.xml代码 ?收藏代码
  1. <?xml?version="1.0"?encoding="utf-8"?>??
  2. <manifest?xmlns:android="http://schemas.android.com/apk/res/android"??
  3. ??????package="com.learning.example"??
  4. ??????android:versionCode="1"??
  5. ??????android:versionName="1.0">??
  6. ????<application?android:icon="@drawable/icon"?android:label="@string/app_name">??
  7. ????????<activity?android:name=".Download"??
  8. ??????????????????android:label="@string/app_name">??
  9. ????????????<intent-filter>??
  10. ????????????????<action?android:name="android.intent.action.MAIN"?/>??
  11. ????????????????<category?android:name="android.intent.category.LAUNCHER"?/>??
  12. ????????????</intent-filter>??
  13. ????????</activity>??
  14. ??
  15. ????</application>??
  16. ????<uses-sdk?android:minSdkVersion="8"?/>??
  17. ??
  18. <!--?访问网络和操作SD卡?加入的两个权限配置-->??
  19. <uses-permission?android:name="android.permission.INTERNET"/>??
  20. <uses-permission?android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>??
  21. </manifest>???

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下载助手类httpdownloader 代码 ?收藏代码
  1. package?com.learning.example.util;??
  2. ??
  3. import?java.io.BufferedReader;??
  4. import?java.io.File;??
  5. import?java.io.IOException;??
  6. import?java.io.InputStream;??
  7. import?java.io.InputStreamReader;??
  8. import?java.net.HttpURLConnection;??
  9. import?java.net.MalformedURLException;??
  10. import?java.net.URL;??
  11. ??
  12. public?class?HttpDownloader?{??
  13. ??????
  14. ????private?URL?url?=?null;???
  15. ??????
  16. ????/**??
  17. ?????*?根据URL下载文件,前提是这个文件当中的内容是文本,函数的返回值就是文本当中的内容??
  18. ?????*?1.创建一个URL对象??
  19. ?????*?2.通过URL对象,创建一个HttpURLConnection对象??
  20. ?????*?3.得到InputStream??
  21. ?????*?4.从InputStream当中读取数据??
  22. [email protected]
  23. [email protected]
  24. ?????*/??
  25. ????public?String?download(String?urlStr){??
  26. ????????StringBuffer?sb?=?new?StringBuffer();??
  27. ????????String?line?=?null;??
  28. ????????BufferedReader?buffer?=?null;??
  29. ????????try?{??
  30. ????????????url?=?new?URL(urlStr);??
  31. ????????????HttpURLConnection?urlConn?=?(HttpURLConnection)url.openConnection();??
  32. ????????????buffer?=?new?BufferedReader(new?InputStreamReader(urlConn.getInputStream()));??
  33. ????????????while(?(line?=?buffer.readLine())?!=?null){??
  34. ????????????????sb.append(line);??
  35. ????????????}??
  36. ??????????????
  37. ????????}???
  38. ????????catch?(Exception?e)?{??
  39. ????????????e.printStackTrace();??
  40. ????????}??
  41. ????????finally{??
  42. ????????????try?{??
  43. ????????????????buffer.close();??
  44. ????????????}?catch?(IOException?e)?{??
  45. ????????????????e.printStackTrace();??
  46. ????????????}??
  47. ????????}??
  48. ????????return?sb.toString();??
  49. ????}??
  50. ??
  51. ????/**??
  52. ?????*???
  53. [email protected]
  54. [email protected]
  55. [email protected]
  56. [email protected]
  57. ?????*??????-1:文件下载出错??
  58. ?????*???????0:文件下载成功??
  59. ?????*???????1:文件已经存在??
  60. ?????*/??
  61. ????public?int?downFile(String?urlStr,?String?path,?String?fileName){??
  62. ????????InputStream?inputStream?=?null;??
  63. ????????try?{??
  64. ????????????FileUtils?fileUtils?=?new?FileUtils();??
  65. ??????????????
  66. ????????????if(fileUtils.isFileExist(path?+?fileName)){??
  67. ????????????????return?1;??
  68. ????????????}?else?{??
  69. ????????????????inputStream?=?getInputStreamFromURL(urlStr);??
  70. ????????????????File?resultFile?=?fileUtils.write2SDFromInput(path,?fileName,?inputStream);??
  71. ????????????????if(resultFile?==?null){??
  72. ????????????????????return?-1;??
  73. ????????????????}??
  74. ????????????}??
  75. ????????}???
  76. ????????catch?(Exception?e)?{??
  77. ????????????e.printStackTrace();??
  78. ????????????return?-1;??
  79. ????????}??
  80. ????????finally{??
  81. ????????????try?{??
  82. ????????????????inputStream.close();??
  83. ????????????}?catch?(IOException?e)?{??
  84. ????????????????e.printStackTrace();??
  85. ????????????}??
  86. ????????}??
  87. ????????return?0;??
  88. ????}??
  89. ??????
  90. ????/**??
  91. ?????*?根据URL得到输入流??
  92. [email protected]
  93. [email protected]
  94. ?????*/??
  95. ????public?InputStream?getInputStreamFromURL(String?urlStr)?{??
  96. ????????HttpURLConnection?urlConn?=?null;??
  97. ????????InputStream?inputStream?=?null;??
  98. ????????try?{??
  99. ????????????url?=?new?URL(urlStr);??
  100. ????????????urlConn?=?(HttpURLConnection)url.openConnection();??
  101. ????????????inputStream?=?urlConn.getInputStream();??
  102. ??????????????
  103. ????????}?catch?(MalformedURLException?e)?{??
  104. ????????????e.printStackTrace();??
  105. ????????}?catch?(IOException?e)?{??
  106. ????????????e.printStackTrace();??
  107. ????????}??
  108. ??????????
  109. ????????return?inputStream;??
  110. ????}??
  111. }??

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文件操作类fileutils 代码 ?收藏代码
  1. package?com.learning.example.util;??
  2. ??
  3. import?java.io.File;??
  4. import?java.io.FileOutputStream;??
  5. import?java.io.IOException;??
  6. import?java.io.InputStream;??
  7. import?java.io.OutputStream;??
  8. ??
  9. import?android.os.Environment;??
  10. ??
  11. public?class?FileUtils?{??
  12. ????private?String?SDPATH;??
  13. ??????
  14. ????private?int?FILESIZE?=?4?*?1024;???
  15. ??????
  16. ????public?String?getSDPATH(){??
  17. ????????return?SDPATH;??
  18. ????}??
  19. ??????
  20. ????public?FileUtils(){??
  21. ????????//得到当前外部存储设备的目录(?/SDCARD?)??
  22. ????????SDPATH?=?Environment.getExternalStorageDirectory()?+?"/";??
  23. ????}??
  24. ??????
  25. ????/**??
  26. ?????*?在SD卡上创建文件??
  27. [email protected]
  28. [email protected]
  29. [email protected]
  30. ?????*/??
  31. ????public?File?createSDFile(String?fileName)?throws?IOException{??
  32. ????????File?file?=?new?File(SDPATH?+?fileName);??
  33. ????????file.createNewFile();??
  34. ????????return?file;??
  35. ????}??
  36. ??????
  37. ????/**??
  38. ?????*?在SD卡上创建目录??
  39. [email protected]
  40. [email protected]
  41. ?????*/??
  42. ????public?File?createSDDir(String?dirName){??
  43. ????????File?dir?=?new?File(SDPATH?+?dirName);??
  44. ????????dir.mkdir();??
  45. ????????return?dir;??
  46. ????}??
  47. ??????
  48. ????/**??
  49. ?????*?判断SD卡上的文件夹是否存在??
  50. [email protected]
  51. [email protected]
  52. ?????*/??
  53. ????public?boolean?isFileExist(String?fileName){??
  54. ????????File?file?=?new?File(SDPATH?+?fileName);??
  55. ????????return?file.exists();??
  56. ????}??
  57. ??????
  58. ????/**??
  59. ?????*?将一个InputStream里面的数据写入到SD卡中??
  60. [email protected]
  61. [email protected]
  62. [email protected]
  63. [email protected]
  64. ?????*/??
  65. ????public?File?write2SDFromInput(String?path,String?fileName,InputStream?input){??
  66. ????????File?file?=?null;??
  67. ????????OutputStream?output?=?null;??
  68. ????????try?{??
  69. ????????????createSDDir(path);??
  70. ????????????file?=?createSDFile(path?+?fileName);??
  71. ????????????output?=?new?FileOutputStream(file);??
  72. ????????????byte[]?buffer?=?new?byte[FILESIZE];??
  73. ????????????while((input.read(buffer))?!=?-1){??
  74. ????????????????output.write(buffer);??
  75. ????????????}??
  76. ????????????output.flush();??
  77. ????????}???
  78. ????????catch?(Exception?e)?{??
  79. ????????????e.printStackTrace();??
  80. ????????}??
  81. ????????finally{??
  82. ????????????try?{??
  83. ????????????????output.close();??
  84. ????????????}?catch?(IOException?e)?{??
  85. ????????????????e.printStackTrace();??
  86. ????????????}??
  87. ????????}??
  88. ????????return?file;??
  89. ????}??
  90. ??
  91. }??

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主程序类download 代码 ?收藏代码
  1. package?com.learning.example;??
  2. ??
  3. import?com.learning.example.util.HttpDownloader;??
  4. ??
  5. import?android.app.Activity;??
  6. import?android.os.Bundle;??
  7. import?android.view.View;??
  8. import?android.view.View.OnClickListener;??
  9. import?android.widget.Button;??
  10. ??
  11. public?class?Download?extends?Activity?{??
  12. ????private?Button?downlaodTxtButton?;??
  13. ????private?Button?downlaodMP3Button?;??
  14. ??????
  15. [email protected]
  16. ????public?void?onCreate(Bundle?savedInstanceState)?{??
  17. ????????super.onCreate(savedInstanceState);??
  18. ????????setContentView(R.layout.main);??
  19. ????????downlaodTxtButton?=?(Button)findViewById(R.id.downloadTxt);??
  20. ????????downlaodTxtButton.setOnClickListener(new?DownloadTxtListener());??
  21. ??????????
  22. ????????downlaodMP3Button?=?(Button)findViewById(R.id.downloadMp3);??
  23. ????????downlaodMP3Button.setOnClickListener(new?DownloadMP3Listener());??
  24. ????}??
  25. ??????
  26. ????class?DownloadTxtListener?implements?OnClickListener{??
  27. ??
  28. [email protected]
  29. ????????public?void?onClick(View?v)?{??
  30. ????????????HttpDownloader?downloader?=?new?HttpDownloader();??
  31. ????????????String?lrc?=?downloader.download("http://172.16.11.9:8080/test/1.lrc");??
  32. ????????????System.out.println(lrc);??
  33. ????????}??
  34. ??????????
  35. ????}??
  36. ??????
  37. ????class?DownloadMP3Listener?implements?OnClickListener{??
  38. ??
  39. [email protected]
  40. ????????public?void?onClick(View?v)?{??
  41. ????????????HttpDownloader?downloader?=?new?HttpDownloader();??
  42. ????????????int?result?=?downloader.downFile("http://172.16.11.9:8080/test/1.mp3",?"voa/",?"1.map3");??
  43. ????????????System.out.println(result);??
  44. ????????}??
  45. ??????????
  46. ????}??
  47. }??

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Notice:访问网络和操作SD卡 记得加入的两个权限配置

<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

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